Leading communication technologies in IoT
The world is getting ready to embrace IoT as more and more big brand manufacturers are getting on board with the technology. The exciting promise of interconnectedness of all devices is nothing short of science fiction, but the closer we’re approaching it, the more evident is its lack of a unifying standard.
Here’s a short overview of the leading communication technologies fighting for dominance in the IoT standard war.
ZigBee vs Bluetooth
In terms of standards, the key players in the IoT communication technologies are Zigbee and Bluetooth. Bluetooth is the most intuitive pick when it comes to short-range communication, but once you get a better hold of IoT, it becomes evident that Zigbee is better suited for specific applications. For once, there is already a strong alliance formed behind it, including industry giants like: IKEA, Centrica, ARM, Philips, Comcast and AT&T – producers who jointly amount to more than 2,500 compatible IoT devices, and the list is still growing.
Zigbee uses low data rates and is characterized by low power consumption, while Bluetooth uses higher volumes of data, has higher power consumption (about 1W) with large packet devices. By contrast, BLE (Bluetooth Low Energy) takes just 10 to 100mW.
In terms of speed, ZigBee takes just 30 milliseconds to join a network (against three seconds for Bluetooth), and thus is better for critical, e.g. safety-related applications like self-driving cars communicating to traffic light systems. In this way, Zigbee aims at reliable automation whereas Bluetooth aims at connectivity of mobile devices in close proximity.
Because of its architecture, ZigBee networks have higher latencies as individual nodes in the network have to relay information from one to the other. ZigBee doesn’t cope well with high density of nodes (e.g. in a factory environment). ZigBee also faces a lot of challenges when budget is an important factor, like mobile nodes or parking sensors.
Zigbee networks support longer range devices and more in number compared to Bluetooth networks whose range is small. Also, with 128-bit encryption, Zigbee was designed with security in mind, and is in this regard unparalleled by other IoT standards. Zigbee is widely adopted in various sensors and industrial applications.
ZigBee is a mesh network protocol designed to carry small amounts of data across medium distances. It runs on a mesh network – information from a single sensor node travels across a group (or “mesh”) of modes until the transmission reaches the gateway.
With range up to 100 meters, ZigBee transmits data further by utilizing a mesh network of devices – each device acts as a node relaying the data onwards to device it is intended for.
Just like Bluetooth, WiFi is another popular technology being adapted to the needs of IoT. Nothing beats it when it comes to speed, but it’s not particularly not well-suited for some applications – specifically for creating mesh networks of low-power IoT devices which should communicate reliably with little maintenance.
WiFi’s inherent incompatibility with IoT devices lead to the introduction of new specifications: 802.11ah and 802.11ax, aimed at low-power devices. However, the standard hasn’t been widely adopted yet.
The undeniable advantage of WiFi in the context of IoT is that it can utilize existing networks, especially in places where power efficiency in not a priority: home automation and in-house energy management. In many other IoT applications like body implants, the standard is not the best choice.
Comparison of IoT communication technologies. Source
The two leading cellular formats for IoT are LTE-M and NB-IOT. These standards allow to utilize existing cell network infrastructure (GSM, 3G, 4G, 5G), but because they are designed specifically for IoT, they only transfer little amounts of data.
The LTE-M standard is best suited to applications in which fast data transfer and big coverage is crucial. Think self-driving cars or life-saving systems in so-called “smart cities” – which require immediate reaction times.
NB-IoT, which stands for “Narrowband-IoT,” is the slower version of LTE-M.
And the Winner Is?
The impossibility to call the winner of the standard war stems from the fact that each technology was designed with a clear goal in mind, and comes with its own share of benefits and issues. For example, there is always a compromise to be made between power consumption, range, bandwidth, and per-device cost.
WiFi is good for transferring high volumes of data, but is characterized by higher power usage than most of the other protocols. Cellular utilizes existing mobile phone networks but may prove unreliable in areas with poor coverage. Bluetooth is low-power, but its range is limited. NFC is fast, but won’t cut it for transferring big amounts of data. The list goes on.
The safest prediction here is that producers of IoT devices will have to make their products compatible with at least a couple of leading standards (as was the case with DVD players compatible with DVD plus and DVD minus discs, or NTSC and PAL formats in VHS players). Alternatively, specific standards will become the norm in their respective applications, and live alongside one another.